Beta Carotene and Cataracts in Smokers

Date:

26-Mar-2003

Source

Arch Ophthalmol

Related Monographs

Consumer Data: Beta-Carotene Ocular Health
Professional Data: Beta-Carotene Ocular Health

Article

A cataract is a clouding of the lens sufficient to reduce vision. Most cataracts develop slowly as a result of the aging process, and lead to a gradual reduction in vision. The only treatment is surgical extraction of the opacified lens. Remarkable technical innovations have made it possible to remove the cataract while leaving the lens capsule intact. A plastic or silicone lens is then placed in the empty lens capsule, replacing the natural lens, and most generally leading to improved sight in most patients. Epidemiological studies have also found that people with cataracts have lower serum levels of vitamins C, E, and carotenoids than control subjects.

Beta-carotene belongs to a group of plant compounds called carotenoids. These are the pigments that provide the yellow, orange, and red coloration in fruits and vegetables. Beta-carotene is the most abundant carotenoid in human foods and is generally thought to be the most important carotenoid for humans. Enzymes in the intestines also convert beta-carotene to vitamin A whenever it is needed.

A recent study investigated the long-term effects of beta-carotene and the risk of cataracts in a placebo-controlled study. Over 22,000 male physicians were recruited for this trial. During this 12-year study, participants received either 50 mg of beta-carotene on alternate days, or placebo. The results showed that there was no difference in the overall incidence of cataracts between the placebo or beta-carotene groups. After further analysis, the researchers found that smokers in the beta-carotene group had fewer incidences of cataracts than smokers in the placebo group. The authors concluded that, “among current smokers at baseline, beta carotene appeared to attenuate their excess risk of cataract by about one fourth.”1

References

1. Christen WG, et al. A Randomized Trial of Beta Carotene and Age-Related Cataract in US Physicians. Arch Ophthalmol. 2003;121:372-378.